Tube closures



R. T. GORTON TUBE CLOSURES July 5, 1966 2 Sheets$heet 1 Filed June 18, 1964 INVENTOR. fi wJ/fw WM V HTTORMEY-S y 5, 1966 R. T. GORTON 3,259,298

TUBE GLOSURES Filed June 18, 1964 2 Sheets-Sheet 2 IN VENTOR.

BY $4 M 50 7% fl w g4 HT TOR United States Patent 3,259,298 TUBE CLUSURES Robert T. Gorton, Newtown, Conn, assignor to 3. Curtis and Son Incorporated, a corporation of Connecticut Filed June 18, 1964, Ser. No. 376,083 12 Claims. (Cl. 22923) This invention relates to tube closures and, more particularly, to an insertable paperboard closure for use with a plastic packaging tube.

One type of package which is commonly used at the present time, comprises an extruded plastic tube which is closed at each end by a suitable plug. Such packages, for example, are often formed of transparent plastic and are used to simultaneously contain and display products, such as tooth brushes, perfume, containers of medicinal ointment and the like. In packages of this type, it is customary to employ either two removable plastic plugs at the ends of the tube or, alternatively, one plug is sealed in place and the other is removable. with this type of construction is that printed copy is usually required and the cost of printing on the plastic caps is quite high. Plugs formed of paperboard would be desirable but would not normally be expected to remain snugly positioned in the tube end and might also be driven in so far that they would be difiicult to withdraw.

Accordingly, it is a primary object of the present invention to provide an improved plug for use with tubular containers. Other objects are to provide such a plug which may be manufactured of paperboard, which may be easily inserted and removed into the ends of the tube, which is held tightly in the tube ends so as not to be easily displaced, and which may be folded fiat for transportation.

The manner in which the foregoing objects are achieved will be more apparent from the following description, the appended claims and the figures of the attached drawing, wherein:

FIG. 1 illustrates a tubular package utilizing a plug constructed in accordance with the present invention, a portion of the tube being shown broken away to more clearly illustrate the plug;

FIG. 2 is a front elevational view of the plug employed in the package of FIG. 1, partially broken away to illustrate its construction;

FIG. 3 is a front elevational view of the plug of FIG. 2 shown inserted in the end of a plastic tube;

FIG. 4 is a perspective view of a variation of the plug of FIGS. 1-3 designed specifically for use in a tube of trapezoidal cross section;

FIG. 5 is a front elevational view of the plug of FIG. 4 shown in place in a tube end, portions of the tube and plug being broken away to illustrate the construction;

FIG. 6 is an illustration of still another plug constructed in accordance with the invention shown folded for insertion into the end of a tube of trapezoidal cross section;

FIGS. 7 and 8 illustrate the manner in which the plug of FIG. 6 is set up after insertion into a tube end;

FIG. 9 is an illustration showing the plug of FIGS. 68 completely set up within the tube end;

FIG. 10 is a cross section taken along the line 1010 of FIG. 9;

FIG. 11 illustrates a blank used in constructing the plug of FIGS. 13;

FIG. 12 illustrates a blank used for constructing the plug of FIGS. 4 and 5; and

FIG. 13 illustrates a blank used for constructing the plug of FIGS. 6-10.

The objects of this invention are achieved by providing a paperboard insert plug having a portion arranged to extend beyond the edges of the tube for simplified with- The difficulty 'ice drawal of the plug and to limit is insertion, said plug having a wedging action against the inner surface of the tube.

With particular reference to FIG. 1, there is illustrated an extruded transparent plastic tube 10 of rectangular cross section. Into each end of the tube 10, there is inserted a plug 12 constructed-in accordance with this invention. The plug 12 is illustrated more clearly in FIG. 2. Basically, plug 12 may be considered to be a paperboard box but with certain important features. The entire plug is formed from a single sheet of paperboard and includes a front side panel 14, a top panel 16, a back side panel 18, a bottom panel 20 and two side wings 22, 24 which extend from the bottom panel 20. A glue flap 26 also extends from bottom panel 20 and is adhesively secured to the inner side of the front wall 14.

Reference may now be had to the blank illustrated in FIG. 11 for a clearer understanding of the construction of plug 12. In each of the illustrated blanks, fold lines are indicated by the dash-dot lines. The first feature to be noted is that the ends of the front and back panels 14 and 18 are not straight but are, in fact, tapered with their widest dimensions lying along the fold lines adjoining the top panel 16. The wider dimension of the front and back panels is chosen such that it is approximately the same as the inner dimension of the tube 10. Accordingly, the result is to provide a finished plug which is tapered as illustrated in FIGS. 2 and 3 for easy insertion into the end of the tube 10. A second important feature which should be noted is that the top panel 16 is longer than the longest dimensions of the front and back panels 14, 18, thereby creating projecting edges 16a, 16b. The dimensions of the top panel are such that the edges 16a, 16b extend beyond the edges of the tube 10 when the plug is inserted. This is illustrated most clearly in FIG. 3. As a final important feature, it will be obvious that the wings 22, 24 are not secured to the remainder of the plug except along their fold lines adjoining bottom panel 20. Accordingly, the natural resiliency of the paperboard causes end wings 22, 24 to tend to spring outwardly as illustrated in FIG. 2.

In forming the plug 12, a blank, as illustrated in FIG. 11, is first provided which is folded along the indicated fold lines. A suitable adhesive 27 is applied to the glue flap 26 and glue flap 26 is then cemented to the front panel 14. The resulting plug, which is shown in FIG. 2, is then inserted into the end of the tube 10 as shown in FIG. 3. The taper of the front and back panels allows the plug to be easily inserted and the end wings 22, '24 are forced inwaridly by the sides of the tube until each occupies a space between the back panel 18 and the side formed by front panel 14 and glue flap 26. At the same time, the projecting edges 16a, 16b prevent the plug from being inserted so far as to prevent its easy withdrawal. The edges 16a, 16b, additionally form lips which may be easily grasped by the fingers to remove the entire plug. The natural resiliency of the paperboard causes the wings 22, 24 to exert outward pressure against the inner surface of the tube 10 which prevents the plug 12. from being easily shaken loose.

FIGS. 4 and 5 illustrate a plug construction which is similar to that of FIGS. 13 but is specifically designed for use with a trapezoidal tube 28. The plug 30- of FIGS. 4 and 5 includes a top panel 32 of trapezoidal configuration and wider than the corresponding dimension of the tube 28 so as to provide the edges 32a, 32b extending beyond the edge of the tube 28. A glue flap 34 extends from the narrow side of the top panel 32 and a back panel 36 extends from the longer side of top panel 32. A trapezoidal bottom panel 38 is arranged to be parallel to top panel 32 and is of similar shape but smaller dimensions. The side edges of back panel 36 taper 3 slightly toward bottom panel 38. A front panel 40 having slightly tapered side walls is secured to the glue flap 34. The end wings 42, 44 are hingedly secured to the non-parallel sides of the trapezoidal bottom panel 38.

The blank for constructing the plug of FIGS. 4 and 5 is illustrated in FIG. 12. In the blank of FIG. 12, the adhesive 46 is applied to the glue flap 34 which is there upon secured to the inner side of panel 4ft. In this construction, as in that previously described, the tapered side edges of back panel 36 and front panel 40 provide a tapered finished plug wherein the external dimensions of the bottom panel 38 relative to the tube 28 allow it to be easily inserted into the end of the tube as shown in FIG. 5. Also, the top panel 32 includes extended edges 32a, 32b which limit the insertion of the plug and facilitate its removal.

In FIGS. 6-10 and 13, there is illustrated a plug 46 which differs in certain respects from those previously described. The plug 46 is designed to fit a tube of trapezoidal cross section; however, it can be readily modified to fit a tube of rectangular cross section. The important difference between the FIGS. 6l0 and 13 embodiment of the invention is that the plug is not designed with a taper. However, a snug fit within a tube, ease of insertion, and a gripping action against the inner surface of the tube 48 are achieved by other means. In this embodiment, the completed plug is designed to be slightly oversized as compared to the inner dimensions of the tube 48. The plug functions by being inserted into the tube end in a folded condition and being set up into its full three dimensional form after it has been inserted.

Reference to FIG. 13 will reveal the blank from which the plug 46 is constructed. This blank includes a back panel 50 having joined thereto hinged side wings 52, 54. To one end of the back panel 50 there is connected a glue flap 56 and the other end of the back panel is connected to top panel 58. Top panel 58 is designed as the previously described embodiments in that it is of a larger dimension than the cross section of the tube 48 so as to form projecting edges 58a, 58b. The shorter parallel side of top panel 58 is connected to a front panel 60 which in turn connects with a bottom panel 62. A suitable adhesive 64 is applied to the glue flap 56 which is then secured to the inner surface of the bottom panel 62.

To insert the plug 46, it is first folded as shown in FIG. 6, with the side wings 52, 54 overlying the collapsed front panel 60 and the bottom panel 62 (not shown). In this state, the collapsed plug may be easily inserted into the end of the tube 48 as illustrated. The plug is inserted until the corners formed by the projecting edges 58a, 58b contact the end edges of tube 48 and limit further movement. Upon being released, the natural resilience of the paper board causes the various elements of the plug to spring apart as illustrated in FIG. 7. The plug is then set up by exerting finger pressure against the top panel 58 thus forcing the front panel 60 inward and upward as shown in FIG. 8. In this embodiment, the wings 52, 54 have a width slightly less than the distance between the fully extended front panel 60 and the back panel 50 and a length slightly less than that of front panel 60. Accordingly, as finger pressure against top panel 58 is maintained, front panel 60 continues to be advanced outwardly until, at the point where it contacts the front surface of tube 48, the wings 52, 54 snap behind the edges of the bottom panel 62 so as to form a complete box as illustrated in FIG. 9. The completed plug has considerable rigidity and, as will be noted from the cross section of FIG. 10, completely fills the interior of the tube 48. This insures a snug fit 0f the plug within the tube. However, the projecting edges 58a, 581; still allow the plug to be withdrawn when desired.

It will be noted that each plug illustrated herein may be folded fiat for shipping, even after it has been glued. This is because, in each embodiment, two opposite end flaps or wings are left unconnected so that the resulting configuration is that of an unstable square which may be easily collapsed. It will also be noted that each plug is seated tightly within the tube but may be easily withdrawn.

It will be apparent that each of the embodiments described above achieves the objectives hereinbefore set forth. It will also be apparent to those skilled in the art that a number of variations and modifications may be made in this invention without departin from its spirit and scope. Accordingly, it is to be understood that the above disclosure is illustrative only rather than limiting. This invention is limited only by the scope of the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A box-like separable insert plug for a container tube which comprises: an upper surface member arranged to close the open end of said tube and extend beyond said open end to be grasped by the fingers and limit insertion of said plug into said tube; a lower surface member arranged to be positioned within said tube substantially parallel to said upper surface member; first and second side members interconnecting said upper and lower surface members; and wing member means each hingedly connected along one side edge to said plug, the other side edges being free of said plug and outwardly biased therefrom.

2. The plug of claim 1 wherein said wing member means comprises a first wing member and a second wing member, each hingedly connected to said plug and each having a free edge arranged to bear resiliently against the inner surface of said tube.

3. The plug of claim 2 wherein said first and second wing members are connected respectively to opposite edges of said first side member.

4. The plug of claim 2 wherein said first and second Wing members are connected, respectively, to opposite edges of said lower surface member.

5. The plug of claim It wherein said first and second side members are tapered, the linear dimension of each of said side members at its juncture with said lower surface member being less than the linear dimension at its juncture with said upper surface member.

6. The plug of claim 1 wherein each of said upper and lower surface members is rectangular.

7. The plug of claim 1 wherein each of said upper and lower surface members is trapezoidal.

8. The plug of claim 1 wherein said lower surface member is similar to but smaller than the cross section of said tube.

9. The plug of claim 3 wherein each of said first and second side members and said first and second wing members is substantially rectangular.

10. The plug of claim 9 wherein the linear dimension of each wing member perpendicular to its connected edge is less than the maximum distance from said edge to said second side member and the linear dimension parallel to said connected edge is less than the length of said second side member between said upper and lower surface members.

11. A tubular package which comprises: a tube having a quadrilateral cross section and a first and a second end; and a separable paperboard insert arranged for insertion within said first end to close said tube, said insert includ ing a planar top surface member extending beyond two opposite edges of said tube, first and second tapered planar side members depending from said top surface member into said tube, a planar bottom surface member interconnecting said side members, and first and second wing members each having one side edge hingedly connected to said bottom surface member and extending upwardly along the inner surface of said tube, the other side edges of each wing member being free of said plug in resilient bearing relationship against the sides of said tube terminating in said opposite edges.

12. A tubular package which comprises: a tube having a quadrilateral cross section and a first and a second end; and a separable paperboard insert arranged for insertion Within said first end to close said tube, said insert including a planar top surface member extending beyond two opposite edges of said tube, first and second planar side members depending from said top surface member into said tube and along its interior sides, a planar bottom surface member interconnecting said side members, and first and second wing members each having one side edge hingedly connected to an opposite edge of said first side member and positioned between said first and second side members and against the interior surface of said tube.

References Cited by the Examiner UNITED STATES PATENTS GEORGE O. RALSTON, Primary Examiner. 

1. A BOX-LIKE SEPARABLE INSERT PLUG FOR A CONTAINER TUBE WHICH COMPRISES: AN UPPER SURFACE MEMBER ARRANGED TO CLOSE THE OPEN END OF SAID TUBE AND EXTEND BEYOND SAID OPEN END TO BE GRAPSED BY THE FINGERS AND LIMIT INSERTION OF SAID PLUG INTO SAID TUBE; A LOWER SURFACE MEMBER ARRANGED TO BE POSITIONED WITHIN SAID TUBE SUBSTANTIALLY PARALLEL TO SAID UPPER SURFACE MEMBER; FIRST AND SECOND 